Swedish defense company Saab recently released a new anti-tank ammunition, HEAT 758, specially designed to deal with the high-tech armor of contemporary main battle tanks. The ammunition is used in Saab's "Carl Gustav" 84 mm recoilless gun system and is said to be able to effectively deal with a variety of advanced protection solutions including modern explosive reactive armor.
Over the past century or so, there has been a trade-off between armor and anti-armor technology, which is far more complicated than the simple picture of "cannonballs striking iron bumps" in film and television works. During World War I, tanks still used mild steel armor fixed with rivets, which could be penetrated by powerful rifles. By World War II, with the optimization of steel alloy composition, improvement of metallurgical technology, and increase in armor thickness, coupled with the tilted arrangement of armor to guide deflected projectiles and disperse impact energy, tank protection capabilities were significantly enhanced.
Correspondingly, anti-tank weapons have also evolved rapidly, from the German "Iron Fist" and "Tank Killer" to the American "Bazooka" and the British PIAT successively adopts shaped charge warheads, which concentrate the explosive energy into high-temperature metal jets and penetrate thick steel plates with smaller calibers. Later, composite armor composed of steel, ceramics and composite materials appeared to resist new generation attack methods such as depleted uranium high-speed armor-piercing projectiles. During this evolution, explosive reactive armor (ERA) has become a key part of tank protection: a large number of steel boxes containing high-energy explosives are installed on the outside of the vehicle body. When hit by a shaped charge, the explosives actively detonate to destroy and deflect incoming warheads or explosion shock waves with reverse impact.
As ERA technology continues to be upgraded, defense contractors are also forced to simultaneously "roll" to a higher technical threshold. The HEAT 758, which was publicly displayed in Karlskoga, Sweden, is the latest generation of ammunition developed for the "Carl Gustav" family recoilless rifles that have been in service since the Cold War. It is aimed at heavy armor targets equipped with modern explosive reactive armor, including mainstream systems such as Kontakt-1, Kontakt-5 and Relikt.
HEAT 758 is a "tandem armor-breaking" anti-tank ammunition, but it has made important improvements in its working mechanism. The traditional tandem warhead relies on a front small charge to detonate the ERA box first, peeling off the outer layer of protection, and then the rear main charge penetrates the exposed steel armor. Although this configuration is theoretically clear, the explosion itself in the previous stage will also disrupt the formation and stability of the subsequent main jet. Saab adopted the so-called "non-initiating precursor" (NIP) solution this time and tried to take advantage of the "sweet spot" of ERA in detonation sensitivity by redesigning the second-stage structure and action process.
The article points out that in actual applications, explosives are not as easily detonated as popular imagination: glycerine dynamite will not explode immediately when dropped, colloidal explosives can be thrown like plasticine, and even TNT may just burn rather than explode violently in a campfire. In order for the main charge to detonate, it is often necessary to "relay" the detonating chain and the detonator with increasing sensitivity. This puts forward subtle requirements for explosive reactive armor: on the one hand, it must be sensitive enough to enemy ammunition to ensure that it can reliably trigger when hit; on the other hand, it must not accidentally explode when a tank slightly collides or rear-ends a civilian vehicle. HEAT 758 is targeting this sensitivity window by controlling the strike intensity of the precursor so that it is enough to penetrate the ERA box and open the shaped charge jet channel, but not enough to trigger the explosion of the explosive in the box, thereby opening a "clean" armor-breaking path without detonating the ERA.
According to Saab, in order to find this critical condition, the company used artificial intelligence to approximate the process of ammunition hitting the target. 50,000 digital simulations are performed to optimize various parameters. HEAT 758 also integrates Firebolt technology. Through the digital communication link between the ammunition body, the "Carl Gustav" M4 launcher and the 558 fire control device, it automatically obtains data such as ammunition type information and charge temperature, and calculates the best ballistic solution in real time to improve the hit and kill effects.
In terms of specific performance, HEAT 758 can penetrate homogeneous rolled armor with a thickness of up to 100 mm within an effective range of 700 meters and a muzzle velocity of approximately 255 meters/second. Weighing approximately 7 kilograms per round and less than 1 meter in length, the round is sheathed in a carbon fiber composite material and lined with titanium alloy for structural strength and heat resistance. Saab revealed that this type of ammunition has entered the mass production stage, and the identity of the buyer has not yet been disclosed.
Michael Hoglund, head of Saab's ground combat business unit, said that HEAT 758 is the company's response to changes in battlefield situations. When explosive reactive armor became a "threshold" that traditional ammunition was difficult to overcome, the new ammunition once again reduced the threat posed by armored vehicles to front-line soldiers through technological upgrades. This also reflects Saab's R&D line of continuing to tap the potential of active platforms and improve combat effectiveness.